1. Technical Field
The present development relates to grommets and more particularly to sealing an opening in a panel.
2. Background Art
In automotive vehicle applications, there are various vehicle body panels through which a wiring harness is passed, such as the firewall or door panels. Typically, an opening is punched, or otherwise formed, in the body panel. A grommet is fitted into the opening, with the grommet having a passage through which the wiring harness can be threaded. A cross-section of a grommet installed into a body panel, according to the prior art, is shown in FIG. 1. A body panel 2 has an opening into which a grommet 4 is installed. Grommet 4 has multiple wires forming a wiring harness 6 passing through a tubular portion 8 of grommet 4. Typically, tape 10 is wrapped around the wiring harness 6. Grommet 4 has a channel 12 (or groove) into which a portion of panel 2 near the opening is held. The opening in panel 2 and channel 12 are sized to cooperate when installed. On either side of channel 12, grommet 4 is larger in circumference than the opening in panel 2. An insertion force is applied to grommet 4 so that one of the sides adjacent to channel 12, which is larger than the opening in panel 2, deforms. As inserted, an edge of the opening of panel 2 is engaged with channel 12 with contact on three sides of channel 12.
The grommet is provided for a number of reasons. If the panel through which the wires travel is between an inside compartment and a harsher environment, the grommet provides a seal so that water, fumes, dust, etc. that might be part of the harsher environment are largely prevented from entering the inside compartment. If the grommet is placed in a body panel with a noisy environment on one side, another function of the grommet is to limit the transmission of noise from one side to the other through the opening in the panel.
Some body panels through which wires may be passed are sufficiently stiff preventing excessive deformation when a grommet is inserted and providing a surface to which the grommet can be secured and sealed. Such an example is shown in FIG. 1, where panel 2 is flat, or nonflanged, at the opening.
In some applications, a flange is formed on the panel opening, an example of which is shown in FIGS. 2 and 3, according to the prior art. Panel 20 has an opening 22 with a flange 24 formed near opening 22. Flange 24 resists deformation in panel 20 in the region around opening 22. In FIG. 2, grommet 26 is shown uninstalled. Grommet 26 has a wiring harness 28 inserted through a cylindrical portion 30 of grommet 26. Tape 32 is applied near a tip of grommet 26. In the example shown in FIG. 2, grommet 26 has a conical section 34. Grommet 26 has a channel 36 for accepting plate 20. Channel 36 has a first surface 38, second surface 40, and third surface 42. Extending from third surface 42 is a lip 44.
In FIG. 3, grommet 26 is shown installed into opening 22 of panel 20. Surface 40 has a raised portion on which flange 24 rests. First surface 38 contacts a first side 46 of panel 20. A second side 48 of panel 20 is in contact with a tip of lip 44. Because the tip is thin in cross section, it deforms readily and provides little force on panel 20 when installed. Consequently, the sealing force is minimal. Also, grommet surface 38 deforms easily because it is a thin wall. When deformed upon engagement with panel 20, it contacts side 46 of panel 20 along the length of first surface 38.
It is known to design channels in grommets to accommodate non-flanged panel openings, such as shown in FIG. 1, and to accommodate flanged panel openings, such as shown in FIG. 3. It would be desirable, however, to have a single grommet design that can be used for both flanged and non-flanged panel openings and one that exerts a strong sealing force to prevent water, dust, fumes, noise, etc. to pass through the grommet.